Evidence-Based Reviews

Driving with dementia: How to assess safety behind the wheel

Current Psychiatry. 2008 December;7(12):37-48

References

1. Stowell-Ritter A, Straight A, Evans EL. Understanding senior transportation: report and analysis of a survey of consumers age 50+. Washington, DC: American Association of Retired Persons; 2002.

2. Marottoli RA, de Leon CFM, Glass TA, et al. Consequences of driving cessation: decreased out-of-home activity levels. J Gerontol B Psychol Sci Soc Sci 2000;55(6):S334-40.

3. Marottoli RA, Mendes de Leon CF, Glass TA, et al. Driving cessation and increased depressive symptoms: prospective evidence from the New Haven EPESE. Established Populations for Epidemiologic Studies of the Elderly. J Am Geriatr Soc 1997;45(2):202-6.

4. Hebert LE, Scherr PA, Bienias JL, et al. Alzheimer disease in the US population: prevalence estimates using the 2000 census. Arch Neurol 2003;60(8):1119-22.

5. Jang RW, Man-Son-Hing M, Molnar FJ, et al. Family physicians’ attitudes and practices regarding assessments of medical fitness to drive in older persons. J Gen Intern Med 2007;22(4):531-43.

6. Herrmann N, Rapoport MJ, Sambrook R, et al. Predictors of driving cessation in mild-to-moderate dementia. CMAJ 2006;175(6):591-5.

7. Hedlund J. Countermeasures that work: a highway safety countermeasure guide for state highway safety offices. Washington, DC: National Highway Traffic Safety Administration; 2006.

8. Dobbs B. Medical conditions and driving: a review of the literature (1960-2000). Washington, DC: National Highway Traffic Safety Administration; 2005. Available at: http://www.nhtsa.dot.gov/people/injury/research/Medical_Condition_Driving/pages/TRD.html. Accessed September 29, 2008.

9. Li G, Braver ER, Chen LH. Fragility versus excessive crash involvement as determinants of high death rates per vehicle-mile of travel among older drivers. Accid Anal Prev 2003;35(2):227-35.

10. Physician’s guide to assessing and counseling older drivers. Washington, DC: National Highway Traffic Safety Administration; 2003. Available at: http://www.nhtsa.dot.gov/people/injury/olddrive/OlderDriversBook. Accessed September 29, 2008.

11. Yeudall LT, Reddon JR, Gill DM, et al. Normative data for the Halstead-Reitan neuropsychological tests stratified by age and sex. J Clin Psychol 1987;43(3):346-67.

12. Brown LB, Ott BR, Papandonatos GD, et al. Prediction of on-road driving performance in patients with early Alzheimer’s disease. J Am Geriatr Soc 2005;53(1):94-8.

13. Determining medical fitness to operate motor vehicles. CMA driver’s guide. 7th ed. Ottawa, Ontario, Canada: Canadian Medical Association; 2006.

14. Molnar FJ, Patel A, Marshall SC, et al. Systematic review of the optimal frequency of follow-up in persons with mild dementia who continue to drive. Alzheimer Dis Assoc Disord 2006;20(4):295-7.

15. Rapoport MJ, Herrmann N, Molnar FJ, et al. Psychotropic medications and motor vehicle collisions in patients with dementia (letter). J Am Geriatr Soc 2008;56(10):1968-70.

16. Molnar FJ, Patel A, Marshall SC, et al. Clinical utility of office-based cognitive predictors of fitness to drive in persons with dementia: a systematic review. J Am Geriatr Soc 2006;54(12):1809-24.

17. Rapoport MJ, Herrmann N, Molnar FJ, et al. Sharing the responsibility for assessing the risk of the driver with dementia. CMAJ. 2007;177(6):599-601.

18. Herrmann N, Gauthier S, Lysy PG. Clinical practice guidelines for severe Alzheimer’s disease. Alzheimers Dement 2007;3(4):385-97.

19. Hogan DB, Bailey P, Carswell A, et al. Management of mild to moderate Alzheimer’s disease and dementia. Alzheimers Dement 2007;3(4):355-84.

19. Assessing fitness to drive for commercial and private vehicle drivers. Sydney, Australia: National Library of Australia; 2006. Available at: http://www.austroads.com.au/aftd/index.html. Accessed November 4, 2008.

21. Medical aspects of fitness to drive. A guide for medical practitioners. Wellington, New Zealand: Land Transport Safety Authority; 2002. Available at: http://www.transfund.govt.nz/licensing/docs/ltsa-medical-aspects.pdf. Accessed September 29, 2008.

22. At a glance guide to the current medical standards of fitness to drive. Swansea, UK: Drivers Medical Group, Driver and Vehicle Licensing Agency; 2008. Available at: http://www.dvla.gov.uk/medical/ataglance.aspx. Accessed September 29, 2008.

23. Man-Son-Hing M, Marshall SC, Molnar FJ, Wilson KG. Systematic review of driving risk and the efficacy of compensatory strategies in persons with dementia. J Am Geriatr Soc 2007;55(6):878-84.

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25. Duchek JM, Carr DB, Hunt L, et al. Longitudinal driving performance in early-stage dementia of the Alzheimer type. J Am Geriatr Soc 2003;51(10):1342-7.

26. Ott BR, Heindel WC, Papandonatos GD, et al. A longitudinal study of drivers with Alzheimer disease. Neurology 2008;70(14):1171-8.

27. Molnar FJ, Byszewski AM, Marshall SC, Man-Son-Hing M. In-office evaluation of medical fitness to drive: practical approaches for assessing older people. Can Fam Physician 2005;51:372-9.

Algorithm: 3 options for drivers with dementia, based on in-office assessment
* Observe legislation or statutes that address reporting unsafe drivers to the department of motor vehicles or ministry of transportation

On-road driving tests

Because some individuals with mild dementia can drive safely for extended periods, international recommendations for assessing the driver with dementia emphasize on-road driving tests.^{10,13,20–22} American¹⁰ and Canadian guidelines¹³ suggest that a dementia diagnosis is not sufficient to withdraw licensure.

Clinical Point

Sometimes it helps to give the patient a prescription in his name that says, ‘Do not drive.’ Provide a copy to the family to use as a reminder

A formal driving assessment is necessary to establish road safety for patients with mild dementia except when the need for license withdrawal is evident, such as when the patient has:

a history of major driving problems (such as crashes or driving the wrong way on a highway)
significant contraindications to driving on the history or physical examination (such as severe inattention or psychosis).

Challenges of on-road testing. On-road tests may be the gold standard, but they are not without clinical problems.

Need to retest. Because almost all dementias are progressive and driving skills deteriorate over time, most guidelines recommend periodic retesting. For patients with dementia who pass on-road evaluations, limited evidence supports retesting every 6 months.¹⁴ Take an individual approach, however, because of the various rates at which the dementias progress.

Testing vs real world conditions. Structured on-road testing is not equivalent to unstructured real-world driving, in which the patient often must navigate without instruction or assistance.

Rural vs urban driving. Road tests conducted in urban areas assess skills associated with complex conditions and the need to respond quickly to crises. They might not assess as well rural driving, which requires sustained attention on monotonous roads.

Inaccessibility. Cost and lack of availability of on-road tests, particularly in rural areas, limit the number of patients whose performance can be evaluated.

CASE CONTINUED: Distressing results

Mr. D has a history of decline in cognition and function, objective cognitive difficulties, and a subtle history of driving problems. You refer him for a specialized on-road test, and the report indicates that he failed. Errors included wide turns, driving too slowly, getting caught in an intersection twice during red lights while attempting to turn left, driving on the shoulder, and failing to signal lane changes. You review the results with Mr. D and his wife and recommend that he cease driving immediately.

Clinical Point

Driving restrictions, cognitive enhancers, and passenger ‘co-pilots’ have not reduced crash rates in studies of drivers with dementia

Mr. D is furious, and his wife is dismayed. He demands to know how he can continue to play golf, which is his only form of exercise and recreation. Will she have to give up her bridge club? How will they shop for food? They request permission to at least to drive to the grocery store during the daytime.

You explain that no system allows individuals to drive only at certain times, and for the sake of safety you cannot grant them special permission. You discuss alternatives, such as asking their daughter for assistance with grocery shopping and taking taxis or ride-sharing with friends who play golf and bridge.

Remain firm, but ease the blow

Driving cessation orders distress patients, families, and clinicians. A failed road test clearly indicates unsafe driving, and driving cessation is critical to public safety.

Clinical Point

In a prospective study, all patients with mild dementia were found to be unsafe drivers by the end of 2 years

A review by Man-Son-Hing et al²³ found that drivers with dementia performed worse than nondemented controls in all studies that examined driving performance (on-road, simulator, or caregiver report). Simulators showed problems such as off-road driving, deviation from posted speed, and more time to negotiate left turns.²⁴

By comparison, only 1 of 3 studies using state crash records showed an increased risk of collisions in persons with dementia compared with controls.²³ From a research perspective, however, studies that use state-reported collisions to assess driving risk are confounded by driving restrictions on persons with dementia.

Mr. D wants to continue driving with restrictions. No studies have shown reduced crash rates when drivers with dementia used compensatory strategies such as restrictions, retraining/education, having a passenger “co-pilot,” on-board navigation, or cognitive enhancers.²³

If Mr. D had passed the road test, the situation would have been more ambiguous. Two studies have examined on-road driving performance over time in patients with early-stage dementia.^25,26 Both studies followed drivers prospectively for 2 years, and those with mild dementia (vs very mild or no dementia) were most likely to show a decline in driving skills: